1. Field of the Invention
The present invention pertains generally to lampholders for receiving lamps, and more particularly to a family of lampholders for use with low wattage medium base metal halide lamps which reject inappropriately dimensioned lamps.
2. Description of the Prior Art
The prior art teaches metal halide lamps which include a relatively centrally located arc tube situated within the confines of an outer glass bulb. These arc tubes are conventionally made of quartz and operate at extremely high temperatures and relatively high pressures. Under certain undesirable conditions, a system failure or internal factors will result in a safety hazard being created, whereby a violent shattering of the arc tube will send hot glass and lamp parts into contact with the bulb glass which, in turn, will break, releasing the hot glass and lamp parts into the surrounding environment. Under such conditions, there is an obvious risk of severe personal injury, fire and/or property damage.
For this reason normally such conventional metal halide lamps are supported within what are referred to as "enclosed" fixtures whose structure is designed to contain violently released hot glass and lamp parts. A cover lens is used in such fixtures. In addition, significant reductions in such potential violent failures can be achieved by relamping before the rated end of the life of the lamp. Another conventional manner in which such potential violent failures are reduced includes the user's periodically turning off the lamp to permit its cooling, so that upon relighting, a non-violent or less violent lamp failure is facilitated.